The most commonly used signal transduction mechanism in eukaryotes involves seven transmembrane receptors that activate heterotrimeric G proteins. G proteins mediate the effects of a vast array of signaling molecules including neurotransmitters, hormones, cytokines, the majority of pharmaceutical and addictive drugs, as well as the senses of vision and olfaction. In 1996, Regulators of G Protein Signaling (RGS) proteins were discovered as a fundamental component of the G protein signaling mechanism. Dozens of RGS proteins exist in humans. They are defined by a G protein GTPase activation domain that acts to terminate signaling, but often have multiple other domains whose functions are the subject of active investigation. This application seeks support for the Third RGS Protein Colloquium, to be held April 4-5, 2008 in San Diego, CA. The Colloquium will be satellite of the Experimental Biology 2008 conference. Its association with this massive conference ensures a high level of publicity for the Colloquium and will increase participation by making attendance convenient. Financial support will be used to fund travel to the meeting by speakers, and to encourage the participation of young scientists by reducing their costs. The RGS Protein Colloquia have emerged as the sole meeting devoted to RGS proteins, and provide an essential forum to allow investigators in this field to interact with each other, most of them young and/or new to this fast-growing field. A group of outstanding speakers have already committed to the Colloquium, including established leaders in the RGS field as well as new investigators. A set of additional speakers will be chosen from among meeting registrants to provide more opportunities for investigators who are young or new to the field. Two poster sessions will provide opportunities for yet more young scientists to present their work and also will facilitate interaction among all attendees. Sessions at the meeting will be devoted to the following topics: 1) RGS structure/function; 2) RGS targeting/cellular localization; 3) Novel interactions/functions; 4) RGS action in vivo. Meeting materials will be made available to the public via the conference web site to increase the impact of the Colloquium. [unreadable] [unreadable] [unreadable]